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Altera_Forum
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16 years ago

Altera FFT simulation

I'm working with Altera streaming 256 point FFT core. I've discovered the errata on the core (V9) rearding mismatch between the Matlab sims and HDL sims and the limit on the input range. Looki...
Altera_Forum's avatar
Altera_Forum
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16 years ago

For FraGuidi

I don't use CLKEN as I can guarantee a constant stream of input data so I don't have any knowledge about how to deal with it. Sorry.

For Gianfranco

Don't know if you're still seeing the mismatches on your outputs. Everything you're describing sounds right to me.

Here's how I call the fft model in Matlab.

[outputrow, exp_out] = fft128_8b_model(inputrow,128,0);

I'm running image frames thru so I need to save results in arrays so I save the fft data in "outputrow" and the exponent out in "exp_out".

I don't see that you tell the model whether it's a forward or inverse transform. I feed it a zero which is a forward transform. (It probably defaults to zero in the model.)

Nothing is jumping out at me wrt what you are seeing.

Anybody else have any input for gianfranco?